The present invention provides a manually operable quick connect and disconnect tool holder assembly permitting to mount a tool in a tool supporting element of a machine, with high positional precision with respect to the centering of the tool as well as with respect to its angular orientation. More particularly, the present invention has particular applications for mounting an electrode tool on the end of the servo controlled linearly movable quill or ram of an electro-erosion machining apparatus, such as, for example, an electrical discharge machining apparatus.
Many devices have been designed for holding an electrode tool on the end of the quill or ram of an EDM machine, such as, for example, the electromagnetic electrode holder disclosed in U.S. Pat. No. 2,978,616 but few, if any, of such devices are capable of combining accurate centering of the electrode tool with precise angular positioning of the tool in a quick connect and disconnect device permitting to rapidly interchange tools when so required. It is known to mount a tool by way of a tapered bore adapted to accept the taper-shank of the tool, such holder providing a highly accurate centering of the tool. However, such holder devices are generally not provided with means permitting to effectuate precise angular positioning of the tool.
The tool holder assembly of the invention permits to effectuate a rapid coupling and uncoupling of an electrode tool with the movable element, quill or ram, of an EDM machine. In addition, the mating elements may be easily cleaned, with the result that repetitive and precise centering of the electrode tool is assured. Furthermore, the elements forming the tool holder assembly of the invention are relatively few and they are easily manufactured, such that a tool holder according to the invention is relatively low in cost.
To insure precision in the manufacture of an electrode tool designed for co-operating with the tool holder assembly of the invention, it is advantageous to mount the tool holder blank on a conventional machine tool by means of the tool holder assembly of the invention during machining of the electrode tool. If, for example, the electrode tool is made on a shaper to a particular shape requiring locating relative to predetermined angular positions, a high precision of the centering and angular positioning of the electrode tool blank is required during machining, and holding the electrode tool blank on the conventional machine tool during machining by means of the holder assembly of the invention presents the advantage of holding the electrode tool during its machining in the same position and with the same precision as will subsequently be the case when the electrode tool is mounted on the ram of an EDM machine.